Core Issues Side Ops
by Getful
Summary: Based off of Niccole's Core Issues series. Contains an OC. Fanfiction of a fanfiction.
1. Detour

**This story is based on/inspired by the Core Issues Series by Nicolle. Any other AUs mentioned in here belong to their creators. Toby Fox owns Undertale. I only created the OC nothing else.**

Takes place during season 1

The highway was empty of cars, the noise barriers on the both sides had vines growing as nature slowly took back the land. A lone figure walked down the highway with a duffle bag strapped over his right shoulder and an AK on the left. The figure wore a cap, light jacket with two pockets in front, and wool gloves. Cargo pants with a belt that had eight pouches were complimented with running boots. A pattern less bandana that stuck to his face finished the look. Everything he wore was grey.

He came to a stop in a clearing, away from the highway, away from anything for that matter. A hand sized rock popped up from the ground, then another right next to it, then another till they all formed a circle. The figure left, and the orange on the ground soon turned to black. He returned with sticks which were roughly dumped into the circle. Sitting down he bent his legs in front of him and held a hand at the pile, a few seconds later the pile was a small fire.

A bird was chirping on a tree, nearby smoke was rising into the air from a circle of rocks. Sitting on two logs facing each other were the lone figure and a short skeleton wearing a hoody and pink slippers. The lone figure pulled a box out of a pocket and flicked the top. Pulling out two sticks he bit one through his bandana and held the other to the skeleton. The skeleton put his hand in front of him shaking his head. "I don't smoke."

The figure slid the unused cigarette back into the box before putting said box back into his pocket. He stood up with the cigarette sideways and shouldered the duffle bag onto the ground. "Badges are in that, around a hundred to two hundred." He turned his back onto the skeleton, "Hopefully they haven't moved the factory yet, you'll probably have to check on that."

The skeleton picked up the duffle bag single handedly and shouldered it. "Are you coming back to the Foundation?"

The figure shook his head, "I got a follow up to this, this was a deviation from what I was supposed to be doing."

"What were you supposed to be doing pal?"

"Rescuing you, although I don't think you know that. That version of you that is Sans."

 **On a less confusing note today is September 15, Undertale's anniversary.**


	2. Rescue

**This story is still based on/inspired by Niccole's Core Issues series. Any other AUs mentioned here will always belong to their creators. Toby Fox owns Undertale.**

Takes place during season 1

A medieval castle, a moat with piranhas, this wasn't new except for the piranhas. Considering that grassy plains surrounded the castle the piranhas were probably shipped here, and considering who was inside the castle it wouldn't be too difficult. Around the castle there was a bit of ground, just enough to move by putting his back against the wall and edge slowly towards the corner tower. A figure could be seen sidling against the walls of the castle. Said figure wore a snapback cap, a hoodie which covered all of him except for a bit of the skin on his neck. Around the hands were wool gloves and the feet running boots. The cargo pants had rounded cargo pockets filled with something. A tinted ski goggle with an oversized strap covered most of his hair and skin on his head. A bandana that stuck to his face finished the look. Everything was grey as usual. If he fell at least there was company in the moat.

A voice spoke, deeply mechanical yet it felt as if the mechanical part was just a filter. **"Remember the plan?"**

A hand shot up to the strap where his ear should be, two fingers held up to activate the receiver. "Grab friendlies and keep it quiet."

" **How are you going to extract them?"**

Sliding up to the bottom of the corner tower he stopped and looked up. "Bothering a biomedical engineer to redirect another agent to assist is… not good for them and for us in the category of time, the jammer is still up?"

" **Yes. Also files transferred."**

His left arm came up, looking at the device similar to a phone strapped to his forearm. Different grey windows popped up and files cycled themselves giving him a short view of the faces and names. "Files received, did you?"

" **I learned from last time. No hacking otherwise C or Fase would kill me."**

He turned around and faced the wall, stuck his fingers into the crevices between stone bricks and began climbing up. Halfway up he stopped as the mechanical voice spoke again.

" **Heads up, recently missing Sans, went missing around the time you left for this."**

He looked right, "Found him."

 **A sigh, "We are going to get reprimanded for this."**

"We aren't the ones who jumped him." He was still looking at the Sans who wore a blue scarf around his neck and a blue cape.

"Human! I, the magnificent Sans, am here to help you!"

" **We're so screwed, time to pack it up and go home."**

A handed landed on the magnificent Sans's shoulder, "How'd you get here?"

"I, the magnificent Sans, used one of your royal gauntlets!"

He looked down at Sans's forearm and was not surprised by a phone like device strapped to the skeleton's arm bones. "Smart, I think you can help me Sans."

"I can!? I mean of course!"

He nodded and pointed upwards towards the window on the corner tower, "some people are going to be coming out, and when they do they need someone to lead them home. Can you do this?"

"Of course human!"

He pointed towards the plains. "I need you to wait there right behind that hill, when you see some friends bring them home."

"Well human, I, the magnificent Sans shall wait there."

He watched as the small skeleton jumped down the wall and jumped across the moat in a single bound towards the hill in the distance.

" **You think his brother knows about this?"**

"If not he can ask me if he's interested." He resumed climbing the wall, "Remind me to go fishing later."

" **I thought you don't forget."**

"You know what I mean. And send Agent Serif and Root Command the files."

…I hope the Foundation didn't forget. Forget about us. It's been… actually I don't know how long it's been with Chara pulling my bone. According to them they got "a bone to pick with me"… more like half my rib cage. They'd turned this medieval castle into a base, on the outside it looked like something out of a storybook. On the inside was where things got weird, the ceilings and walls were still made out of stone brick, but there were light bulbs and computers around the whole place. They even installed running water here, heating, and electric locks with keypads on the doors. That's all I saw before they tied me up and left me here.

"Hey there comedian," great the last person I wanted to hear. A hand grabbed my skull and yanked my head so hard I thought my head might fall off. There was aching in my ribcage. Chara was smiling, crouching in their green and yellow striped shirt holding a knife. "Heya, having a good time?" If they were going to do that I was running out of time.

Their smile got bigger, "You said I was going to have a bad time," the hand released and all I could see was my hoodie unzipped and half my ribs missing.

"I guess you could say the tables have turned," their hand was gripping my skull again and their face was in mine's again. There was an outline of something to the left of Chara, my mind's probably drawing images with the lines between the stone bricks again.

"It's been a good time, but I'm afraid I can't let you stick around anymore, not me but… you know what I mean." The knife was under my chin and getting closer, "If this weren't so important I'm sure they'd see it my way comedian but… maybe next time if your Frisk resets."

Chara released my skull and I saw my unzipped hoodie and ribcage again. Chara was grunting and they were hitting someone's arm? There was additional sound that couldn't have been Chara's arms, were they kicking? This continued for a few moments before the grunting stopped and everything went quiet. "Is anyone there?"

Another hand, this one under my chin and gloved, but it lifted my head slowly. A pair of grey tinted goggles was looking back at me. He was wearing something on his head and the bottom part of his face was grey for some reason. "How many fingers?" Behind him was Chara face first on the floor.

I could barely see and this guy wanted me to take a medical examination? "I don't know, five?"

The other hand went up to his ear, I must be really tired because it looked like his two fingers were pressed against thin air. "Cross reference this."

A few moments passed as those goggles looked back at me, seriously who wore those things? They were ridiculously huge, they probably took up half the guy's face and left no skin to see, or bones if this guy is me.

"Whoa," the ground was leaving me and my chest was suddenly being pressed against fabric. I had a nice view of some sort of strap and the back of a cap. Gloved hands were guiding mines around his neck. Placing them near each other I linked them and held on tight.

"Friendly is in my possession," was this guy with the Foundation or someone else? Only three words popped into my mind.

"Who are you?"

The edge of the goggles suddenly appeared very close to my eye socket. "SCS." SCS stood up which caused everything to blur, was that a pistol in his right hand? The shape looked familiar, the barrel had a little box attached underside of it. Think Bone's Frisk said Socom? And the barrel looked longer and more cylindrical than the others I've seen. We were passing a few blurs of blue, probably windows when suddenly everything went upside down. I wrapped my legs around his stomach as I felt myself peeling off.

SCS was hanging off of a pipe on the ceiling, one ankle on top of the other foot on top of the pipe. Only his hands were grabbing on to the pipe and his feet just stayed on the pipe as we moved along the ceiling. If I were doing this I'd probably hug the pipe and move really slowly arms and all, this guy must have done this before because we were moving at a constant speed without any stops. Why are we on the ceiling anyways?

"Check the trapdoors, check the moat exit, check everywhere! That Sans does not leave here alive!" Oh. It was interesting looking at Chara from this angle with all the other versions of them. All you can see are the different hair styles from above, there was one I was focusing on and was looking at for a while. It stayed in that spot for a while like it was standing guard. That or we weren't moving along the pipe anymore. Wait.

The edge of the goggles appeared on the left, then the right, then the left again. Did he not hear them? I pulled both my hands back a bit and the goggles stopped on the left side. It stayed like this for a while before I got a response.

I could hear him clearly but he was whispering, "That door they're in front of connects to an exit that faces a hill, going back is going to put us on the board."

Put us on the board? Was that code for something? I didn't think I was going to get a response because I couldn't see the edge of his goggles on either side of his head. Then one of his hands left the pipe and went towards a cargo pocket. It ripped the Velcro which surprisingly made no sound and pulled out a flash bang. At least I think it was a flash bang. Bone's Frisk didn't mention the fuse body being colored light green. The hand was moving towards his face and soon I heard a pin pop and saw the cylinder drop.

"Ow, hey watch where you're throwing things."

"I didn't throw anything."

"Then what's that?"

If I were down there I'm sure I would have found this very funny. Right now I was just hoping they wouldn't look up. Then a green gas started exiting with a loud gush and floated up.

"Oh shit gas!"

"Get cleeeaaarrr."

Bodies were hitting the stone bricks and I couldn't help but flinch. Watching for a while the gas dissipated and soon we were upright again. SCS was hanging by both hands off the pipe, he let go and we landed with barely a sound in front of a wooden door with a keypad lock. Moving to the side he stopped and turned around. A glove was tapping my hand and I released both my hands and feet, slowly dropping to the side of the door as SCS moved back in front of it tapping the buttons on the keypad.

"When he opens that door we blast him so hard even a reset can't bring him back."

He was completely focused on the keypad and was muttering, "Nine, nine, nine, nine, nine."

"Get ready."

"His Frisk is going to be sorry they let him out of their sight."

"Nine, nine," a beep sounded and he moved to the other side pulling out another one of those flashbangs with the light green fuse body. SCS turned the handle, pushed the door, and retreated to the side of the door as bullets flew through the doorway. He pulled the pin and threw the cylinder to the side barely scratching the doorframe. Probably to bounce it off a wall.

"Gas!"

There was the sound of gas being pushed out. The torrent of bullets gradually lessened and I couldn't hear any more people on the other side of the doorway. SCS was peeking, his goggles barely exposed through the doorway before he walked over and picked me up. He lifted me over his head and set me on his back again. I linked my hands together around his neck and he started running. We went by the many different versions of Chara and Frisk sleeping on the floor and against the walls. The weapons they carried did not look like paintball guns. At the end of this hallway was another similar wooden door with a mirror next to it.

And another similar person wearing a green and yellow striped shirt waiting for us. They started walking towards us.

"You're going down SCS."

My carrier stopped and held his hands up in fists. "Already been down, just came up for some air."

Chara swung straight with their right getting blocked by SCS's left. SCS grabbed Chara's arm and pulled them in destabilizing them and punched them in the face with his right. While Chara was in the middle of being punched his left hand was pushing their shoulder. Next thing I knew he had Chara in a chokehold with his left arm around their neck. In the mirror a knife came up in his right hand reverse grip, tip barely touching Chara's neck. "Where are your buddies?"

Chara was hitting SCS's neck, then stopped. "They're upstairs or napping, but you know that."

"Where are the rest?"

In the mirror Chara was smiling, "They're upstairs or-"

His left hand pressed harder causing Chara to starting gasping for air, "You know what I mean."

Chara starting his left arm and he released a bit of pressure. Chara was frowning, "Around twenty downstairs."

"Who's your CO?"

Chara's eyes widened, "I can't tell you he'll kill me!"

Nothing as Chara was still in the chokehold, neither talked and I just watched the reflection in the mirror seeing tears streaming down Chara's eyes. They must be scared just by the first two questions and now this. Then the next three words. "Fine by me."

Chara's eyes widened and the knife was put away, right hand coming back just as fast wrapping around Chara's neck with the left and pressing in. Chara starting hitting his arms, eventually the hits became weaker as they then stopped altogether. Chara's arms fell to their sides and SCS released, slowly using his hands to lay them on their back on the floor. I blurted the only thing on my mind.

"Are they dead?"

"Sleeping gas with no side effects and choking only to knock out, I think."

His hand was near where his ear should be on the goggle strap, "Command you hear that?"

I guess he was listening to another voice because his hand stayed there as he opened the door. I just hanged on afraid he would drop me, being half as tall as this guy didn't help. There was a moat outside with those little fish with sharp teeth. SCS turned around so I was over the moat making me grip my own hands tighter and dig my feet into his stomach. If I was hurting him he didn't make a sound. His hands were on the wall as he sidled on the outside toward a wood plank connected to the other side of the moat. When we reached it he stepped on and I braced expecting it to break. I was disappointed but let out a sigh as we reached the other side. All this excitement was making me think about Seraph and the ketchup they had, my vision getting blacker. I barely heard him when we reached a tiny little hill, probably really noticeable among the plains.

"Twenty are accounted for, all friendlies have been extracted."

" **Jumping you and last friendly."**

"Let's go home."


End file.
